Heretofore, as a rear subframe supporting an arm of a rear suspension, there has been known one type which comprises a pair of right and left side member segments each extending in a vehicle front-rear direction and a cross member segment disposed between the pair of right and left side member segments (see the following Patent Literatures 1 and 2).
Specifically, a rear subframe described in the Patent Literature 1 comprises a pair of right and left side member segments (longitudinal members) each having a central portion in the vehicle front-rear direction which is largely curved in such a manner as to protrude inwardly in a vehicle width direction, and two cross member segments (lateral members) each disposed between the pair of right and left longitudinal members.
A rear subframe described in the Patent Literature 2 comprises a pair of right and left side member segments (side members) each having a rear portion in the vehicle front-rear direction which is bent in such a manner as to be located outwardly in a vehicle width direction with respect to a front portion thereof, and two cross member segments (cross members) each disposed between the pair of right and left longitudinal members.
Meanwhile, in addition to weight reduction and downsizing, a rear subframe is required to be enhanced in its own rigidity and in rigidity of a vehicle body-mountable section thereof, in order to enhance suspension arm supporting rigidity in normal state (particularly, rigidity against a load input in the vehicle width direction during vehicle turning). However, on the other hand, in the event of a rear collision, there is a contradictory need for allowing a portion of the rear subframe to be easily deformed, in order to absorb a rear impact load.
In the Patent Literature 1, each of the side member segments is curved, so that it becomes possible to, during a rear collision, cause a rear portion of the side member segment to be bendingly deformed outwardly in the vehicle width direction, and absorb an impact load by means of the bending deformation of the side member segment.
However, because the side member segment is largely curved over its overall front-rear length, a distance between a mountable section as a vehicle body-mountable section, and an arm support section is undesirably increased. This leads to an increase in weight, and means that it is unable to enhance the suspension arm supporting rigidity. Thus, as for the conventional structure disclosed in the Patent Literature 1, there remains a need for further improvement in terms of weight reduction, rigidity enhancement, and downsizing.
In the Patent Literature 2, the rear portion of each of the side member segments is bent outwardly in the vehicle width direction, so that it becomes possible to, during a rear collision, cause the rear portion of the side member segment to be bendingly deformed outwardly in the vehicle width direction, and absorb an impact load by means of the bending deformation of the side member segment.
However, because the bent portion of the side member segment is located rearward of a rear one of the cross members, a distance between a vehicle body-mountable section at a rear end of the side member segment and a suspension arm support section of the side member segment is undesirably increased. This leads to an increase in weight, and means that it is unable to enhance the suspension arm supporting rigidity. Thus, as for the conventional structure disclosed in the Patent Literature 2, there remains a need for further improvement in terms of weight reduction, rigidity enhancement, and downsizing.